Richard Nixon, incumbent Vice-President, campaigned until a few hours beforehand, hadn't fully recovered from an illness and refused make-up (which he thought was effeminate).
Among voters who heard the debate on the radio Nixon's experience trumped Kennedy's youthfulness. But the larger audience who watched on TV thought that Kennedy had won. Kennedy subsequently pulled ahead in the polls and went on to win the election by a nose.
Nixon essentially lost the election because he didn't put on make-up. Or more broadly his advisers didn't understand that TV debates would be different from traditional town halls or the radio. The technology had changed, but their strategy hadn't.
What mistakes are being made in communications today which will look as basic as refusing make-up in 1960?
My starter would be mistaking digital for just another way of broadcasting your message to your audience. Yes it is valuable for broadcasting to large numbers of people - but that's a very narrow way to see it. Facebook's genius is that it realises that a lot of the time, most of us prefer spend time consuming relevant content produced by our amateur friends than from professional entertainers.